Mechanical Characteristics and Adhesion of Glass-Kevlar Hybrid Composites by Applying Different Ratios of Epoxy in Lamination

Sajid Hussian Siyal,Salman Muhammadi,Shahid Hussain,Khalida Naseem,Tahani Saad Algarni,Subhan Ali Jogi,Zubair Ahmed Laghari,Asma Alothman,Muhammad Javed,Sadam Ali Khichi

doi:10.3390/coatings11010094

Abstract

Hybrid composites have great potential for specific strength and specific stiffness, effective in aerospace industries, submarines, and light-weight automotives. The mechanical strength and adhesiveness of hybrid laminates can be enhanced by effective use of matrix materials in different ratios of epoxy resin and epoxy hardener. Gentle use of resin and hardener in the fabrication of hybrid composites can alter tensile modulus, the bonding strength between matrix and fabric. Spectacular progress has been achieved by the selection of appropriate amounts of resin and hardener in the hybridization of composite laminate. Hybridization was made by Kevlar inorganic/organic fabrics and glass fabrics stacked with epoxy matrix material. To achieve the combination of mechanical properties and bonding strength, transparent epoxy resin and hardener of commercial grades mixed in various ratios are incorporated as matrix material to fabricate laminate. Three different sheets, named A (3:2), B (4:1), and C (2:3), were embedded by the hand layup method to prepare a hybrid composite. Experimental tests, according to ASTM 3039, were performed to determine the tensile mechanical properties. Peel tests, according to ASTM 6862-11, were performed to investigate the interlaminar strength between Kevlar and glass layers. Shore A and Shore C hardness durometers were used to find out the hardness of the specimens at different spots using the ASTM D-2240 standard. Finally, physical testing, such as density and then water absorption, was carried out using the ASTM D-570 standard to check the swelling ratio of the different specimens. The results obtained highlight that the specimen of the glass/Kevlar hybrid embedded in the ratio 3:2 in lamination has the best mechanical properties (tensile strength and hardness) and the lowest swelling ratio, while the material system in the ratio 4:1 shows the best interlaminar properties and adhesion capabilities.

Highlights

Composites have distinct phases, made by dissimilar fibers and matrix materials
Matrix materials have a continuous phase and are used as adhesives, and fibers have a discontinuous phase in metal matrix composites (MMCs), ceramic matrix composites (CMCs), and polymer matrix composites (PMCs) [1]
To achieve a balance between the cost competitiveness and the strength-to-weight ratio of laminate, hybrid composites are fabricated by stacking E-glass/Kevlar fibers [15]

Summary

Introduction

Composites have distinct phases, made by dissimilar fibers and matrix materials. Reinforcement fibers or stacking sheets are employed in matrix materials for making composite structures at the macroscopic level. To achieve a balance between the cost competitiveness and the strength-to-weight ratio of laminate, hybrid composites are fabricated by stacking E-glass/Kevlar fibers [15]. Kevlar fibers reinforced with glass fibers have incredible capacity to produce less dense materials with superior strength, which attain high break and bear resistance characteristics [23]. The mechanical properties of composite materials strongly depend on the adhesive material as well as the different ratios in which resin and hardener are mixed together to form a matrix phase [25]. The proper use of adhesive materials can supplement the mechanical properties, reduce component weight, increase durability, provide better design latitude, handle high levels of stress, and increase the strength of composites [26]. Sufficient bonding is essential to take advantage of the stress transfer from the weak matrix to the durable fibers

Results

Discussion

Conclusion